Treasury has a brief write-up on the bonds entitled “Known Examples of Securities.” We have also been asked to date service records from the WWI time frame that also turned out to be counterfeit.In addition, as experts in foreign currency and counterfeit analysis, IPS has trained members of the U. Secret Service and Homeland Security as well as Canadian Border Services Agency in the fundamentals of fiber analysis.The recent exponential growth in the use of image processing software applications has been accompanied by a parallel increase in their use in criminal activities.
The visual appearance of inks is only one clue to their composition.
Sometimes two inks can look identical to the naked eye but further tests may be able to distinguish between them. For example inks can be examined using infra red or ultraviolet reflectance at various wavelengths or using visible light but examining emissions from the ink in the infra red area of the spectrum (infra red luminescence).
Our examiners use an instrument known as a VSC 2000HR to carry out non-destructive specialised lighting examinations.
Inks may also be distinguished by other more complex chemical tests but these are likely to be destructive to some extent.
While exact age dating of papers is not possible, the process is often able to exclude samples as being made in the time period of question.
Walter Rantanen has developed a large database of paper with known ages.
Additionally, entries which have been obliterated may be readable using these methods, for example by rendering the obliterating ink transparent under a particular light source.
Care must be taken when inks are deemed to be indistinguishable using any testing method.
The altered documents were examined using a suite of currently available image processing tools.